Due to the fact that the worldwide energy consumption caused by cooling
devices in buildings has been increasing steadily and also the fact that the
pressure has been rising to provide this cooling energy with environmentally
friendly technology, solar powe.re~ DEC-systems (Desiccative and Evaporative
Cooling) have begun capturing increasing interest over the past few years. ,
However, up to now little experience has been gained in the operation of these
systems and thus currently little information is available about the performance,
the efficiency, the control strategy and the best component choice. This lack of
knowledge has resulted in a low rate of acceptance of, this technology so far.
The studies presented in this thesis serve as a contribution to the advancement
of DEC technology by providing fundamental knowledge about the operation
and attainable performance of these systems.
A comprehensive study of desiccant wheels was undertaken which provides
detailed information about the operation and the achievable dehumidification
performance of this component. A detailed simulation model for desiccant
wheels was developed and verified with measured data from a desiccant wheel
test plant.
Additionally, two commercially used DEC-systems (one in a public library in
Spain and the other in a plastics processing factory building in Germany) were
monitored for the purposes of evaluating the performance of these systems and
resolving existing problems in their operation and control strategies. In spite of
the generally positive validation of the planned and expected cooling
performances in both cases, the monitoring also showed that there are
considerable possibilitiesÃ‚Â· for improvement, especially with the regulation of the
system.